Re: [PATCH v3 0/8] RDMA: Enable operation with DMA debug enabled

Leon Romanovsky
2026-03-17T19:05:47Z

On Mon, Mar 16, 2026 at 09:06:44PM +0200, Leon Romanovsky wrote:
> Add a new DMA_ATTR_REQUIRE_COHERENT attribute to the DMA API to mark
> mappings that must run on a DMA‑coherent system. Such buffers cannot
> use the SWIOTLB path, may overlap with CPU caches, and do not depend on
> explicit cache flushing.
>
> Mappings using this attribute are rejected on systems where cache
> side‑effects could lead to data corruption, and therefore do not need
> the cache‑overlap debugging logic. This series also includes fixes for
> DMA_ATTR_CPU_CACHE_CLEAN handling.
> Thanks.

<...>

> ---
> Leon Romanovsky (8):
> dma-debug: Allow multiple invocations of overlapping entries
> dma-mapping: handle DMA_ATTR_CPU_CACHE_CLEAN in trace output
> dma-mapping: Clarify valid conditions for CPU cache line overlap
> dma-mapping: Introduce DMA require coherency attribute
> dma-direct: prevent SWIOTLB path when DMA_ATTR_REQUIRE_COHERENT is set
> iommu/dma: add support for DMA_ATTR_REQUIRE_COHERENT attribute
> RDMA/umem: Tell DMA mapping that UMEM requires coherency
> mm/hmm: Indicate that HMM requires DMA coherency
>
> Documentation/core-api/dma-attributes.rst | 38 ++++++++++++++++++++++++-------
> drivers/infiniband/core/umem.c | 5 ++--
> drivers/iommu/dma-iommu.c | 21 +++++++++++++----
> drivers/virtio/virtio_ring.c | 10 ++++----
> include/linux/dma-mapping.h | 15 ++++++++----
> include/trace/events/dma.h | 4 +++-
> kernel/dma/debug.c | 9 ++++----
> kernel/dma/direct.h | 7 +++---
> kernel/dma/mapping.c | 6 +++++
> mm/hmm.c | 4 ++--
> 10 files changed, 86 insertions(+), 33 deletions(-)

Marek,

Despite the "RDMA ..." tag in the subject, the diffstat clearly shows that
you are the appropriate person to take this patch.

Thanks.

> ---
> base-commit: 11439c4635edd669ae435eec308f4ab8a0804808
> change-id: 20260305-dma-debug-overlap-21487c3fa02c
>
> Best regards,
> --
> Leon Romanovsky <leonro@nvidia.com>
>